A 28-year-old man with a 6-week history of floaters, blurred vision, and vitritis haze is diagnosed with intermediate uveitis. Systemic investigations are unremarkable. What is the drug of choice for initial management?

Explanation

## Drug of Choice for Intermediate Uveitis **Key Point:** Periocular (sub-Tenon) corticosteroid injection is the first-line treatment for intermediate uveitis because it delivers high local concentration to the vitreous and posterior segment while minimizing systemic side effects. ### Why Periocular Triamcinolone? | Route | Indication | Onset | Duration | Adverse Effects | |-------|-----------|-------|----------|------------------| | **Periocular triamcinolone 40 mg** | Intermediate/posterior uveitis (first-line) | 3–7 days | 3–4 months | Cataract, glaucoma, local atrophy | | **Oral prednisolone** | Severe bilateral/systemic uveitis | 1–2 days | Variable | Infection, GI upset, osteoporosis, hyperglycemia | | **Topical corticosteroids** | Anterior uveitis only | Hours | Days | Minimal systemic absorption | | **Systemic immunosuppressants** | Chronic/steroid-dependent uveitis | Weeks | Months | Bone marrow suppression, hepatotoxicity | **High-Yield:** Intermediate uveitis predominantly affects the **vitreous and pars plana**. Topical corticosteroids cannot reach therapeutic concentrations in the vitreous; periocular injection bypasses the blood–ocular barrier. ### Mechanism of Periocular Injection 1. **Anatomical advantage:** Deposits steroid in sub-Tenon space, diffuses across sclera into vitreous and posterior segment 2. **High local concentration:** Achieves therapeutic levels in vitreous without systemic toxicity 3. **Sustained release:** Microcrystalline suspension provides 3–4 months of anti-inflammatory effect 4. **Reduced systemic burden:** Minimal hepatic metabolism compared to oral therapy **Clinical Pearl:** Intermediate uveitis (also called pars planitis) is often **idiopathic** in developed countries but may be associated with sarcoidosis, multiple sclerosis, or Lyme disease. Periocular triamcinolone is effective in ~70% of cases; repeat injections can be given every 3–4 months. ### When to Use Oral Prednisolone - Bilateral intermediate uveitis - Severe vitritis with vision-threatening complications (cystoid macular edema, epiretinal membrane) - Failure or contraindication to periocular injection - Systemic uveitis (e.g., sarcoidosis, tuberculosis) **Tip:** Always perform **baseline ocular pressure measurement and posterior segment examination** before periocular injection to exclude glaucoma and posterior segment pathology.